JP2007008286A - Telescopic column for vehicle steering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent increase in contraction/extension load, even if a spherical body is smoothly slid with an inner face of a groove in an axial direction when the telescopic column is contracted or extended. <P>SOLUTION: An axial directional groove 5 of a female shaft 2 has enlarged diameter groove parts 21, 22 which are made to be deeper (that is, they have enlarged diameters in a radial direction) through difference in level 20. When the extendable column is assembled in an assembly line of an automobile and when the length of the shaft in assembly is made to be shorter than that in normal use, even if the spherical body 7 is smoothly slid with the inner face of the enlarged diameter part 21 in the axial groove 5, increase in contract load can be prevented. Since the axial directional groove 5 of the female shaft 2 has the enlarged diameter groove part 22, when the extendable column is assembled in the assembly line of the automobile and when the length of the shaft in assembly is made to be longer than that in normal use, increase in extension load can be prevented similarly. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a telescopic shaft for vehicle steering that is incorporated in a steering shaft of a vehicle and has a male shaft and a female shaft that are non-rotatable and slidably fitted to each other.

  The telescopic shaft of the steering mechanism portion of the automobile is required to absorb the axial displacement generated when the automobile travels and to transmit the displacement and vibration on the steering wheel. Further, in order to obtain an optimum position for the driver to drive the automobile, a function of moving the position of the steering wheel in the axial direction and adjusting the position is required.

  In any of these cases, the telescopic shaft is required to reduce the rattling noise, to reduce the rattling on the steering wheel, and to reduce the sliding resistance during the sliding operation in the axial direction. The

  For this reason, conventionally, the male shaft of the telescopic shaft is coated with a nylon film, and grease is applied to the sliding portion to absorb or alleviate metal noise, metal hitting sound, etc., and to reduce sliding resistance. The rotation direction play has been reduced.

  However, there is a case where wear of the nylon film progresses with the progress of use and the play in the rotational direction increases. In addition, under conditions where the engine room is exposed to high temperatures, the nylon membrane changes in volume, and the sliding resistance may increase remarkably or wear may be significantly accelerated, resulting in increased rotational play. .

  For this reason, in Patent Document 1, rolling occurs in the axial relative movement of both shafts between a plurality of pairs of axial grooves formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft. A spherical body is fitted.

  Further, a plate that is a preload elastic body for applying a preload to the male shaft and the female shaft via the spherical body between the radially inward or outward of the spherical body and each pair of axial grooves. A spring is provided.

  Thus, when torque is not transmitted, the spherical body is preloaded by the leaf spring to the extent that there is no backlash with respect to the female shaft, so that backlash between the male shaft and the female shaft can be prevented. The shaft and the female shaft can slide in the axial direction with a stable sliding load without backlash.

  In addition, since the spherical body can be restrained in the circumferential direction by a leaf spring when torque is transmitted, the male shaft and the female shaft prevent backlash in the rotational direction, and torque is applied in a highly rigid state. Can communicate.

  Moreover, in Patent Document 1, a stopper plate that restricts the movement of the spherical body in the axial direction is provided at the end of the male shaft. Further, a protrusion (stopper) formed coaxially with the axial groove is formed on the outer peripheral surface of the inner portion of the male shaft.

In addition, the depth (radial dimension) of these axial grooves is constant over the axial direction.
JP 2004-106599 A

  However, in the case of FIG. 2 of Patent Document 1, as described above, the depth (diameter dimension) of the axial groove is constant over the axial direction.

  When assembling the telescopic shaft in an automobile assembly line, the shaft length during assembly must be shorter than the shaft length during normal use.

  Normally, the length of the axial groove on the male shaft is designed so that the ball rolls in the normal use area, so if you try to make it shorter than the normal use area, the spherical body will come into contact with the stopper in the axial groove. Thus, it slides and slides against the inner surface of the axial groove of the female shaft.

  As a result, the expansion / contraction load at the time of assembly may become high, and the efficiency of assembly work may deteriorate.

  The present invention has been made in view of the circumstances as described above, and when the telescopic shaft contracts or expands, even if the spherical body slides and slides on the inner surface of the axial groove, the contraction / extension load It is an object of the present invention to provide a telescopic shaft for vehicle steering that can prevent an increase in the number of wheels and, in turn, can improve the efficiency of assembly work.

In order to achieve the above object, a vehicle steering telescopic shaft according to the present invention is incorporated in a vehicle steering shaft, and a male shaft and a female shaft are non-rotatably and slidably fitted to each other.
Between at least one row of axial grooves respectively formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, an elastic body is interposed, and rolling elements are interposed.
At least one of the axial groove of the female shaft and the axial groove of the male shaft has an enlarged groove portion or a reduced diameter groove portion having different groove depths through a step.

  Preferably, at least the other of the axial groove of the female shaft and the axial groove of the male shaft has a stopper that restricts the axial movement of the rolling element.

Further preferably, the region where the rolling element rolls and slides between the axial groove of the female shaft and the axial groove of the male shaft is a normal use region,
The area where the rolling element slides and slides with respect to at least one of the diameter-expanded groove part or the diameter-reduced groove part of the female shaft and the male shaft is located outside the normal use area. .

  Preferably, a rigid torque transmission unit that transmits a steering torque by contacting the rigid body between the two shafts is provided.

Preferably, the rigid torque transmitting portion is
A sliding body interposed between at least one other groove direction formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, respectively, and slidingly sliding in the axial relative movement, or It is a spline formed on each of the two shafts.

  According to the present invention, when the telescopic shaft is contracted or extended, even if the spherical body slides and slides on the inner surface of the enlarged diameter groove portion of the axial groove, it is possible to prevent an increase in contraction / extension load, As a result, the efficiency of the assembly work can be increased.

  Hereinafter, a telescopic shaft for vehicle steering according to an embodiment of the present invention will be described with reference to the drawings.

(Overall configuration of vehicle steering shaft)
FIG. 1 is a side view of a steering mechanism portion of an automobile to which a vehicle steering telescopic shaft according to an embodiment of the present invention is applied.

  In FIG. 1, an upper steering shaft portion 120 (a steering column 103 and a swinging shaft 104 rotatably supported by the steering column 103 are attached to a member 100 on the vehicle body side via an upper bracket 101 and a lower bracket 102. A steering wheel 105 attached to the upper end of the steering shaft 104, a lower steering shaft portion 107 connected to the lower end of the steering shaft 104 via a universal joint 106, and a steering shaft joint 108 to the lower steering shaft portion 107. A pinion shaft 109 connected via a pin, a steering rack shaft 112 connected to the pinion shaft 109, and the steering rack shaft 112 is supported to elastically move to another frame 110 of the vehicle body. Steering mechanism from a fixed steering rack support member 113 via 111 is formed.

  Here, the upper steering shaft portion 120 and the lower steering shaft portion 107 use the vehicle steering telescopic shaft (hereinafter referred to as the telescopic shaft) according to the embodiment of the present invention. The lower steering shaft portion 107 is formed by fitting a male shaft and a female shaft. The lower steering shaft portion 107 absorbs axial displacement that occurs when the vehicle travels, and a steering wheel. The performance which does not transmit the displacement and vibration on 105 is required. In such performance, the vehicle body has a sub-frame structure, and the member 100 for fixing the upper part of the steering mechanism and the frame 110 to which the steering rack supporting member 113 is fixed are separated, and the steering rack supporting member 113 is This is required in the case of a structure that is fastened and fixed to the frame 110 via an elastic body 111 such as rubber. As another case, when the steering shaft joint 108 is fastened to the pinion shaft 109, an operator may need to have a telescopic function so that the telescopic shaft is once contracted and then fitted and fastened to the pinion shaft 109. . Further, the upper steering shaft portion 120 at the upper part of the steering mechanism also has a male shaft and a female shaft fitted to each other. The upper steering shaft portion 120 is used for a driver to drive a car. In order to obtain an optimal position, the function of moving the position of the steering wheel 105 in the axial direction and adjusting the position is required, and thus a function of expanding and contracting in the axial direction is required. In all the cases described above, it is possible to reduce the rattling noise of the fitting portion on the telescopic shaft, to reduce the backlash feeling on the steering wheel 105, and to reduce the sliding resistance when sliding in the axial direction. Required.

(First embodiment)
FIG. 2 is a longitudinal sectional view of the telescopic shaft for vehicle steering according to the first embodiment of the present invention.

  FIG. 3 is a half sectional view of the telescopic shaft for vehicle steering according to the first embodiment of the present invention.

  FIG. 5 is a cross-sectional view taken along line VV in FIG.

  As shown in FIGS. 2 and 3, the telescopic shaft for vehicle steering includes a male shaft 1 and a female shaft 2 that are non-rotatable and slidably fitted to each other. A universal joint UJ is connected to the male shaft 1 and the female shaft 2, respectively.

  As shown in FIG. 5, three axial grooves 3 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend on the outer circumferential surface of the male shaft 1. Correspondingly, three axial grooves 5 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend on the inner peripheral surface of the female shaft 2.

  Between the axial groove 3 of the male shaft 1 and the axial groove 5 of the female shaft 2, a plurality of rigid spherical bodies 7 (rolling bodies, which roll when the two shafts 1 and 2 move in the axial direction relative to each other) Ball) is installed to roll freely. The axial groove 5 of the female shaft 2 has a substantially arc-shaped cross section or a Gothic arch shape.

  The axial groove 3 of the male shaft 1 is composed of a pair of inclined planar side surfaces 3a and a bottom surface 3b formed flat between the pair of planar side surfaces 3a.

  A leaf spring 9 is provided between the axial groove 3 of the male shaft 1 and the spherical body 7 so as to contact and preload the spherical body 7.

  The leaf spring 9 has a substantially arc-shaped spherical body-side contact portion 9a that contacts the spherical body 7 at two points, and is bent at a predetermined interval in the circumferential direction with respect to the spherical body-side contact portion 9a. The groove surface side contact portion 9b that can come into contact with the planar side surface 3a of the axial groove 3 of the male shaft 1, and the spherical body side contact portion 9a and the groove surface side contact portion 9b are elastically biased in a direction away from each other. And an urging portion 9c bent so as to have a flat bottom surface 9d facing the flat bottom surface 3b of the axial groove 3.

  The urging portion 9c has a substantially U shape and is bent in a substantially arc shape, and the spherical body side contact portion 9a and the groove surface side contact portion 9b are mutually connected by the bent urging portion 9c. Can be elastically biased so as to be separated from each other.

  This is to make the thickness of the bent portion (the urging portion 9c or the groove surface side contact portion 9b) of the leaf spring 9 constant at any location. This is because the torsional rigidity of the preload portion is not stable if the tip of the bent portion (the urging portion 9c or the groove surface side contact portion 9b) falls apart at each location.

  As shown in FIG. 5, in this embodiment, the spherical body side contact portion 9 a that contacts the spherical body 7 is formed in a substantially arc shape larger than the radius of the spherical body 7. Thereby, a contact surface pressure with the spherical body 7 can be reduced rather than a planar shape.

  As shown in FIG. 5, three axial grooves 4 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend on the outer circumferential surface of the male shaft 1. Correspondingly, three axial grooves 6 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend on the inner peripheral surface of the female shaft 2.

  A plurality of rigid cylindrical bodies 8 (sliding bodies) that slide between the axial grooves 4 of the male shaft 1 and the axial grooves 6 of the female shaft 2 when the two shafts 1 and 2 move relative to each other in the axial direction. , A needle roller) is interposed with a minute gap. The axial grooves 4 and 6 have a substantially circular arc shape or a Gothic arch shape in cross section.

  A small diameter portion 1 a is formed at the end of the male shaft 1. The small diameter portion 1 a is provided with a stopper plate 11 that restricts the axial movement of the needle roller 8. The stopper plate 11 includes an axial preload elastic body 12 (that is, a disc spring) and a pair of flat plates 13 and 13 (that is, plain washers) that sandwich the axial preload elastic body 12.

  That is, in the present embodiment, the stopper plate 11 is fitted to the small diameter portion 1a in the order of the flat plate 13, the axial preloading elastic body 12, and the flat plate 13, and is firmly fixed to the small diameter portion 1a by caulking. .

  Thereby, the stopper plate 11 is being fixed to the axial direction. The fixing method of the stopper plate 11 is not limited to caulking, and may be a retaining ring, a screwing means, a push nut, or the like. Further, the stopper plate 11 is configured such that the flat plate 13 is brought into contact with the needle roller 8 and the needle roller 8 can be appropriately preloaded by the axial preload elastic body 12 so as not to move in the axial direction.

  Further, in the present embodiment, the six axial grooves 3 and 4 and the axial direction are formed on the outer peripheral surface of the male shaft 1 through gaps in the radial direction in the six axial grooves 5 and 6 of the female shaft 2. Six substantially arc-shaped protrusions 15 that are coaxially formed are fitted.

  Therefore, when the spherical body 7 and the cylindrical body 8 are dropped or broken from the male shaft 1 for some reason, the protruding portion 15 of the male shaft 1 is fitted in the axial grooves 5 and 6 of the female shaft 2. Thereby, the male shaft 1 and the female shaft 2 can transmit torque and can play a role of a fail-safe function.

  At this time, since a gap is provided between the axial grooves 5 and 6 and the projection 15, the driver can feel a large backlash on the steering wheel, and the steering system fails. Etc. can be detected.

  Furthermore, since the protrusion 15 of the male shaft 1 is coaxial with the spherical body 7 and the cylindrical body 8 in the axial direction, it also serves as a stopper for restricting the movement of the spherical body 7 and the cylindrical body 8 in the axial direction. The possibility of the body 7 and the columnar body 8 coming off can be reduced, and the fail-safe function can be further improved.

  Furthermore, since the protrusion 15 of the male shaft 1 is coaxial with the spherical body 7 and the cylindrical body 8 in the axial direction, the radial dimension of the male shaft 1 and the female shaft 2 can be reduced to achieve compactness. it can.

  Further, a lubricant may be applied between the axial groove 3 of the male shaft 1, the axial groove 5 of the female shaft 2, the leaf spring 9, and the spherical body 7. A lubricant may also be applied between the axial groove 4 of the male shaft 1, the cylindrical body 8, and the axial groove 6 of the female shaft 2.

  In the telescopic shaft configured as described above, the spherical body 7 is interposed between the male shaft 1 and the female shaft 2, and the spherical body 7 is preloaded to the extent that the female shaft 2 is not rattled by the leaf spring 9. Therefore, the play between the male shaft 1 and the female shaft 2 can be reliably prevented, and when the male shaft 1 and the female shaft 2 move relative to each other in the axial direction, there is no stable play. It is possible to slide with the sliding load.

  At the time of torque transmission, the leaf spring 9 is elastically deformed to constrain the spherical body 7 in the circumferential direction, and the three rows of cylindrical bodies 8 interposed between the male shaft 1 and the female shaft 2 play a main role in torque transmission. Fulfill.

  For example, when torque is input from the male shaft 1, since the preload of the leaf spring 9 is applied in the initial stage, there is no backlash, and the leaf spring 9 generates a reaction force against the torque and transmits the torque. . At this time, overall torque transmission is performed in a state where the transmission torque and the input torque between the male shaft 1, the leaf spring 9, the spherical body 7, and the female shaft 2 are balanced.

  As the torque further increases, the clearance in the rotational direction of the male shaft 1 and female shaft 2 via the cylindrical body 8 disappears, and the subsequent torque increase is transmitted via the male shaft 1 and female shaft 2 to the cylindrical body. 8 communicates. Therefore, it is possible to reliably prevent backlash in the rotational direction of the male shaft 1 and the female shaft 2 and to transmit torque in a highly rigid state.

  As described above, according to the present embodiment, since the cylindrical body 8 is provided in addition to the spherical body 7, most of the load can be supported by the cylindrical body 8 when a large torque is input. Therefore, the contact pressure between the axial groove 5 of the female shaft 2 and the spherical body 7 can be reduced to improve durability, and torque can be transmitted in a highly rigid state at the time of a large torque load. .

  Thus, according to the present embodiment, it is possible to realize a stable sliding load, reliably prevent backlash in the rotational direction, and transmit torque in a highly rigid state.

  The spherical body 7 is preferably a rigid ball. The rigid cylindrical body 8 is preferably a needle roller.

Since the cylindrical body (hereinafter referred to as a needle roller) 8 receives the load by line contact, it has various effects such as a lower contact pressure than a ball receiving a load by point contact. Therefore, the following items are superior to the case where the entire row has a ball rolling structure.
・ The damping effect at the sliding part is larger than that of the ball rolling structure. Therefore, vibration absorption performance is high.
・ Since the needle roller is in minute contact with the male shaft and the female shaft, the fluctuation range of the sliding load can be kept low, and the vibration due to the fluctuation is not transmitted to the steering.
-If the same torque is transmitted, the needle roller can keep the contact pressure lower, so the axial length can be shortened and the space can be used effectively.
-If the same torque is transmitted, the contact pressure of the needle roller can be kept lower, so that an additional step for curing the axial groove surface of the female shaft by heat treatment or the like is unnecessary.
・ The number of parts can be reduced.
・ Assembly can be improved.
・ Assembly costs can be reduced.
As described above, the needle roller serves as a key for transmitting torque between the male shaft 1 and the female shaft 2, and is in sliding contact with the inner peripheral surface of the female shaft 2. The use of the needle roller is superior to the conventional spline fitting as follows.
・ Needle rollers are mass-produced products and are very low cost.
-Since the needle roller is polished after heat treatment, it has high surface hardness and excellent wear resistance.
-Since the needle roller is polished, the surface roughness is fine and the friction coefficient during sliding is low, so the sliding load can be kept low.
-Since the length and arrangement of the needle roller can be changed according to the use conditions, it can be used for various applications without changing the design concept.
・ Depending on the conditions of use, the friction coefficient during sliding may have to be further reduced. At this time, if only the needle roller is surface treated, its sliding characteristics can be changed, so the design philosophy is not changed. Can support various applications.
Since a needle roller having a different outer diameter can be manufactured at a cost of several microns, the gap between the male shaft, the needle roller, and the female shaft can be minimized by selecting the needle roller diameter. Therefore, it is easy to improve the torsional rigidity of the shaft.

  In the present embodiment, the axial groove 5 of the female shaft 2 has the enlarged groove portions 21 and 22 that are deepened through the step 20 (that is, expanded in the radial direction). ing.

  Thus, since the axial groove 5 of the female shaft 2 has the enlarged diameter groove portion 21, when the telescopic shaft is assembled in the assembly line of the automobile, the axial length at the time of assembly is greater than the axial length at the time of normal use. However, even if the spherical body 7 slides and slides with respect to the inner surface of the enlarged-diameter groove portion 21 of the axial groove 5, it is possible to prevent an increase in the shrinkage load, and thus increase the efficiency of the assembly work. Can be planned.

  Further, since the axial groove 5 of the female shaft 2 has an enlarged groove portion 22, when the telescopic shaft is assembled in an automobile assembly line, the axial length during assembly is longer than the axial length during normal use. In this case, even if the spherical body 7 slides and slides on the inner surface of the enlarged-diameter groove portion 22 of the axial groove 5, an increase in the extension load can be prevented, and as a result, the efficiency of the assembly work can be improved. Can do.

  Furthermore, since the axial groove 5 of the female shaft 2 has the enlarged-diameter groove portions 21 and 22, when entering the outside of the normal use region of the enlarged-diameter groove portion 21 in which the groove is deepened (expanded) from the normal use region, The urging force of the spherical body 7 by the leaf spring 9 becomes weak. Therefore, the depth of the enlarged diameter groove portions 21 and 22 to be changed is preferably such that the urging force by the leaf spring 9 acts even outside this normal use region, for example, about 2 mm or less in radius.

  4A to 4C are cross-sectional views showing examples of the shape of the step between the normal use region of the axial groove of the female shaft and the outside of the region.

  As shown in FIG. 4A, the step 20 may be formed at a substantially right angle, or may be formed in a tapered shape as shown in FIG. As such, it may be tapered and wavy.

  Further, the depth (diameter dimension) of the diameter-enlarged groove portions 21 and 22 may have a gradient that gradually changes in the axial direction. For example, you may comprise so that the urging | biasing force to the spherical body 7 may reduce gradually as it distances from a normal use area | region.

  FIG. 6 is a cross-sectional view taken along the line VV of FIG. 3 according to a modification of the first embodiment.

  In this modification, the cylindrical body 8 as a torque transmission member is abolished, and a torque transmission configuration using only a plurality of spherical bodies 7 is adopted. Other configurations, operations, and effects are the same as those in the first embodiment described above.

  FIG. 7 is a cross-sectional view taken along line VV of FIG. 3 according to another modification of the first embodiment.

  In this modification, the cylindrical body 8 as a torque transmission member is eliminated, and instead, a male spline 31 and a female spline 32 are formed on the male shaft 1 and the female shaft 2, respectively. Other configurations, operations, and effects are the same as those in the first embodiment described above.

(Second Embodiment)
FIG. 8A is a half sectional view of a telescopic shaft for vehicle steering according to the second embodiment of the present invention.

  FIG. 9 is a cross-sectional view taken along line IX-IX in FIG.

  In the present embodiment, the basic structure is the same as that of the above-described embodiment, and differences will be described.

  In the present embodiment, the leaf spring 9 is interposed between the inner surface of the axial groove 5 of the female shaft 2 and the spherical body 7. Therefore, the shape of the axial groove 5 is formed substantially the same as the shape of the axial groove 3 of the male shaft 1 in the first embodiment. The axial groove 5 has a planar side surface 5a and a bottom surface 5b, and the configuration and operation thereof are substantially the same as the planar side surface 3a and the bottom surface 3b of the axial groove 3.

  Further, in the present embodiment, the axial groove 3 of the male shaft 1 has a reduced-diameter groove portion 41 having a deepened groove depth (that is, reduced in diameter in the radial direction) via a step 40. .

  Thus, since the axial groove 3 of the male shaft 1 has the reduced diameter groove portion 41, when assembling the telescopic shaft in the assembly line of the automobile, the axial length during assembly is greater than the axial length during normal use. However, even if the spherical body 7 slides and slides with respect to the inner surface of the reduced diameter groove portion 41 of the axial groove 3, it is possible to prevent an increase in the contraction load, and thus increase the efficiency of the assembly work. Can be planned. Other configurations, operations, and effects are the same as those in the first embodiment described above.

  FIG. 8B is a half cross-sectional view of a telescopic shaft for vehicle steering according to a modification of the second embodiment of the present invention.

  In this modification, the axial groove 3 of the male shaft 1 has a reduced-diameter groove portion 42 whose depth is deepened (that is, radially reduced) via a step 40 on the axial end side. ing.

  Thus, since the axial groove 3 of the male shaft 1 has the reduced diameter groove portion 42, when assembling the telescopic shaft in the assembly line of the automobile, the axial length during assembly is greater than the axial length during normal use. However, even if the spherical body 7 slides and slides on the inner surface of the reduced diameter groove portion 42 of the axial groove 3, it is possible to prevent an increase in the extension load, and thus increase the efficiency of the assembly work. Can be planned.

  FIG. 10 is a cross-sectional view taken along line IX-IX of FIG. 8A according to another modification of the second embodiment.

  In this modification, the cylindrical body 8 as a torque transmission member is abolished, and a torque transmission configuration using only a plurality of spherical bodies 7 is adopted. Other configurations, operations, and effects are the same as those of the second embodiment described above.

  FIG. 11 is a cross-sectional view taken along line IX-IX in FIG. 8A according to still another modification of the second embodiment.

  In this modification, the cylindrical body 8 as a torque transmission member is eliminated, and instead, a male spline 31 and a female spline 32 are formed on the male shaft 1 and the female shaft 2, respectively. Other configurations, operations, and effects are the same as those of the second embodiment described above.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

  For example, FIG. 12 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to the present invention. As shown in this drawing, the cylindrical body may be composed of needle rollers 8a. Also in this case, as shown in FIG. 12, the axial groove 5 of the female shaft 2 has an enlarged groove portion 21 whose depth is deepened (that is, radially expanded) through the step 20. Have.

  The axial grooves (5, 6, 3) that slide (axially move) the cylindrical body or spherical body of the male shaft 1 or the female shaft 2 may or may not be subjected to heat treatment.

1 is a side view of a steering mechanism portion of an automobile to which a telescopic shaft for vehicle steering according to an embodiment of the present invention is applied. It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 1st Embodiment of this invention. 1 is a half sectional view of a telescopic shaft for vehicle steering according to a first embodiment of the present invention. (A) thru | or (c) is sectional drawing of the example which shows the shape of the level | step difference between the normal use area | region of the axial groove | channel of a female shaft, and the area | region outside, respectively. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3 according to a modification of the first embodiment. FIG. 5 is a cross-sectional view taken along line VV of FIG. 3 according to another modification of the first embodiment. (A) is a half sectional view of a telescopic shaft for vehicle steering according to a second embodiment of the present invention. (B) is a half sectional view of a telescopic shaft for vehicle steering according to a modification of the second embodiment of the present invention. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. FIG. 10 is a cross-sectional view taken along line IX-IX in FIG. 8A according to another modification of the second embodiment. FIG. 10 is a cross-sectional view taken along line IX-IX in FIG. 8A according to still another modification of the second embodiment. 1 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Male shaft 1a Small diameter part 2 Female shaft 3 Axial groove 3a Planar side surface 3b Bottom surface 4 Axial groove 5 Axial groove 5a Planar side surface 5b Bottom surface 6 Axial groove 7 Spherical body (ball, rolling element)
8 Cylindrical body (needle roller, sliding body)
8a Needle roller with short shaft length 9 Leaf spring (elastic body)
9a Spherical body side contact part (transmission member side contact part)
9b Groove surface side contact portion 9c Energizing portion 9d Bottom surface 10 Telescopic shaft 11 Stopper plate 12 Axial preload elastic body 13 Flat plate 15 Protruding portion 20 Step 21, 22 Expanded groove portion 31 Male spline 32 Female spline 40 Step 41, 42 Contraction Diameter groove portion 100 Member 101 Upper bracket 102 Lower bracket 103 Steering column 104 Steering shaft 105 Steering wheel 106 Universal joint 107 Lower steering shaft portion 108 Steering shaft joint 109 Pinion shaft 110 Frame 111 Elastic body 112 Steering rack 120 Upper steering shaft portion

Claims (5)

In the telescopic shaft for vehicle steering, which is incorporated in the steering shaft of the vehicle and the male shaft and the female shaft are slidably fitted to each other,
Between at least one row of axial grooves respectively formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, an elastic body is interposed, and rolling elements are interposed.
At least one of the axial groove of the female shaft and the axial groove of the male shaft has a diameter-expanded groove portion or a diameter-reduced groove portion having different groove depths through a step, and the vehicle steering expansion / contraction axis.   2. The telescopic shaft for vehicle steering according to claim 1, wherein at least the other of the axial groove of the female shaft and the axial groove of the male shaft has a stopper that restricts the axial movement of the rolling element. The region where the rolling element rolls and slides between the axial groove of the female shaft and the axial groove of the male shaft is a normal use region,
The area where the rolling element slides and slides with respect to at least one of the diameter-expanded groove part or the diameter-reduced groove part of the female shaft and the male shaft is located outside the normal use area. The telescopic shaft for vehicle steering according to claim 1 or 2.   The telescopic shaft for vehicle steering according to any one of claims 1 to 3, further comprising a rigid torque transmitting portion that transmits a steering torque by contacting a rigid body between the two shafts. The rigid torque transmission part is
It is a sliding body that is interposed between at least one row of groove directions formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, respectively, or a spline formed on each of the both shafts. The telescopic shaft for vehicle steering according to claim 4, wherein the telescopic shaft for vehicle steering is provided.

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